I have some difficulties preparing for clear liposomes solutions. Here is what I did, please advise.

*I start off with 0.1g/ml phosphatidylcholine chloroform solution. I thenmove it into a round bottomed flask and dry it in a rotary evaporator. However, instead of getting thin films on the surface, what I end up with is alarge chunk of light yellowish solid. Does that mean I have to use a larger volume of organic solvent?

I then dissolve them into buffer and sonicate. Finally, I got some milky suspension. I assume they are multimellar vesicles. My advisor told me that Icould sonicate to make them unilamellar and make the solution goes clear. I tried, but didn't work.

Could anyone here tell me how to prepare the unilamellar vesicles in a clear solution? More details are better.

you might try this: dissolve PC in EtOH and inject into 20 to 50 fold
volume of buffer with an insulin syringe (or the narrowest needle you
can get) while vortexing. If the EtOH might cause problems downstream,
dialyze against buffer.

There is the classical method of pressing these multilamellar vesicles
through a narrow-pore membrane. However, more consistent results you will
obtain by dissolving the lipids with detergents as mixed micelles and then
striping the detergent away with polystyrene beads (e.g. Biobeads SM2).
Rigaud's group has done extensive work on this, check their papers.

People who don't have funds to afford various lipofection reagents
on the market would probably do well by carefully optimizing
polyethyleneimine-mediated transfection. Lots of reports that suggest
that PEI gives transfection efficiencies comparable to many cationic
lipids.